Dropped passes from the Bears receivers contributed to Glennon's troubles, although he also threw five interceptions and lost three fumbles while playing without his top two receivers. Kevin White and Cameron Meredith, who are on injured reserve.

"We've got to eliminate drops," offensive coordinator Dowell Loggains said. "We need to eliminate the negative runs and the negative plays, because it's really hard to play quarterback when it's second-and-15 and it's a known passing situation."

Although running backs Jordan Howard and Cohen have been effective overall, the running game can improve. They've lost yardage on too many plays, and it's led to an offense ranked 29th in scoring at 15.2 points a game.

"We lead the NFL in plays behind the sticks," Loggains said. "No quarterback can be successful that way."

At least Trubisky will have the benefit of playing with a more cohesive offensive line.

Injuries had taken a toll early, forcing center Cody Whitehair to play guard. Guard Kyle Long returned in Week 3 after recovering from last year's ankle surgery, and all the regular starters played together for the first time against Green Bay in their previous game, a 35-14 loss.

"This is the first time we've had the same offensive line two weeks in a row, and (we're) making sure we're doing exactly what Mitch feels good with — I think he is comfortable with the plan," Loggains said.

Trubisky's ability to improvise can make up for plenty of deficiencies.

"You have to always be available for him (as a receiver) because you never know what he's going to do," Cohen said. "He's very mobile. Just keeping the play alive is something that's he's going to do and we've got to be ready for it."

The Bears rank ninth on defense (306.2 yards a game), but there are problems to be solved there, as well.

For one, they'll have to overcome yet another loss at inside linebacker.

Starter Danny Trevathan has been suspended one game by the NFL for a blow to the head of Green Bay receiver Davante Adams, and the Bears already were without inside linebackers Jerrell Freeman and Nick Kwiatkoski because of pectoral injuries.

So they'll be playing Christian Jones, John Timu and Jonathan Anderson at inside linebacker — the same trio they had at those positions in 2015 before acquiring Trevathan, Freeman and Kwiatkoski.

"Since I've been here, there's been a lot of injuries and different things like that," third-year safety Adrian Amos said about the suspension. "That's one of the things we do have experience with is changing lineups and working with different players.

"That's just how it goes. It's only another adjustment you've got to make."

The defense made lineup changes in the secondary to increase interceptions, after making a franchise record-low of eight each of the past two seasons. And after four games, the Bears are one of four NFL teams without an interception.

"It's just being in the right place and communicating," Amos said. "It's making plays when they come.

"We've got to limit big plays, but also make our plays when they come."